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View Full Version : What's good about collets?



Stephen Tashiro
08-08-2019, 11:32 PM
When is a collet considered the best way to hold a tool bit? - as opposed to a jacobs chuck or a keyless type of device.

On Dremel type rotary tools, I prefer to replace the collet with a chuck. I wonder if there is a way to make this replacement on roto-zip type tools.

I'd be happier if rotary tools used a bit holding arrangement like modern impact drivers. That would require that bits be made with a hexagonal base.

The advantage I see with a collet is that it can soften the shock on the tool by slipping if the bit sticks.

Ole Anderson
08-09-2019, 12:57 AM
In a machine shop, a collet is the preferred way to hold a bit for production, it is generally more accurate and will hold the bit more firmly. I have a mini-mill and have collets for several sizes of drill bits. In my case a #2 Morse taper collet fits into an R8 collet which is held into the mill with a drawbar. I would be leery of turning a mini jacobs chuck, let alone a loose hex quick fit at 25,000 rpms.

Bill Dufour
08-09-2019, 1:11 AM
If the tool is made of hard steel the collet will hold it better. A solid carbide bit will slip in a chuck under load. Drill bits are long enough to be tempered softer at the bottom. Router bits and endmills are so short that the bottom end is still fairly hard after tempering. A three jaw chuck holds less then 50% as much as a collet. A six jaw chuck is better but, much more expensive.
Bill D.

johnny means
08-09-2019, 5:23 PM
A chuck, being much larger, would require a much greater degree of precise balancing than a collet in high RPM situations. I can't imagine that a 1/2" chuck capable of spinning at 12k in a handheld application would be cheap.

Brian Holcombe
08-09-2019, 7:25 PM
I like Albrecht classic chucks and Jacobs super chucks and I still don’t even consider them for accurate work or anything with a side load.

Most Chucks cant grip carbide shanks, with exception to diamond jaw chucks and they hold bits with significantly less contact surface than a collet.

Consider that a collet holds the bit within the spindle where a Chuck holds the bit extended from the spindle.

Brian Holcombe
08-09-2019, 7:35 PM
Albrecht does make a milling chuck, but only in the tapers generally used on high speed mills. So the technology does exist, but it’s not sized for routers.

https://www.albrecht-germany.com/en/products/apcchuck/

Wes Grass
08-10-2019, 2:39 PM
Albrecht calls that a 'chuck', but it's a collet holder. They're a shallow taper, with limited grip range generally suitable only for endmills.

I'm also in the collet whenever possible crowd. The accuracy and finish of drilled holes is clearly better using a collet vs a drill chuck, Jacob's or Albrecht.